Hordeum vulgare

Both maleic acid hydrazide (MH) and gamma ray mutagens significantly alter global histone methylation and acetylation levels in barley. Gamma irradiation exerts a stronger effect on DNA methylation levels compared to MH. This study provides the first immunohistochemical evidence linking mutagenic treatments to specific epigenetic modifications.

Hordeum vulgare

The awn is a bristle-like extension from the tip of the lemma in grasses. In barley, the predominant cultivars possess long awns that contribute to grain yield and quality through photosynthesis. In addition, various awn morphological mutants are available in barley, rendering it a useful cereal crop to investigate the mechanims of awn development. Here, we identified the gene causative of the short and crooked awn (sca) mutant, which exhibits a short and curved awn phenotype. Intercrossing experiments revealed that the sca mutant induced in the Japanese cultivar (cv.) "Akashinriki" is allelic to the independently isolated moderately short-awn mutant breviaristatum-a (ari-a). Map-based cloning and sequencing revealed that SCA encodes the Polycomb group-associated protein EMBRYONIC FLOWER 1. We found that SCA affects awn development through the promotion of cell proliferation, elongation, and cell wall synthesis. RNA sequencing of cv. Bowman backcross-derived near-isogenic lines of sca and ari-a6 alleles showed that SCA is directly or indirectly involved in promoting the expression of genes related to awn development. Additionally, SCA represses various transcription factors essential for floral organ development and plant architecture, such as MADS-box and Knotted1-like homeobox genes. Notably, the repression of the C-class MADS-box gene HvMADS58 by SCA in awns is associated with the accumulation of the repressive histone modification H3K27me3. These findings highlight the potential role of SCA-mediated gene regulation, including histone modification, as a novel pathway in barley awn development.

Hordeum vulgare

Genetic mapping places markers differently than physical mapping in barley chromosome 3H's recombination-poor centromere. FISH with 70 single-copy probes from 65 genetically assigned BAC contigs revealed the centromeric 5.5 cM bin spans 58% of the mitotic metaphase chromosome length. Mitotic and meiotic chromatin in this recombination-poor region is enriched for the heterochromatic mark H3K9me2. In contrast, recombination-enriched subterminal regions are enriched in euchromatic marks H3K4me2, H3K4me3, and H3K27me3. This suggests the meiotic recombination rate is influenced by the chromatin landscape.

Hordeum vulgare

Vernalization in barley promotes flowering by epigenetically activating HvVRN1. Pre-vernalization repression associates with high H3K27me3 at HvVRN1 chromatin. Vernalization increases H3K4me3 and decreases H3K27me3, establishing an active chromatin state. This state maintenance constitutes the epigenetic memory of vernalization in cereals. Unlike Arabidopsis, where vernalization epigenetically represses the floral repressor FLC, cereals epigenetically activate the floral promoter VRN1.

Hordeum vulgare

Four barley Polycomb group (PcG) homologues, HvFIE, HvE(Z), HvSu(z)12a, and HvSu(z)12b, exhibit differential expression across tissues and seed developmental stages and between cultivars with different seed sizes. HvFIE and HvE(Z) expression is responsive to abscisic acid (ABA), implying association with ABA-mediated epigenetic processes during seed development, germination, and stress response. These PcG genes may regulate barley seed development.

Hordeum vulgare

Two barley plant-specific HD2 histone deacetylases, HvHDAC2-1 and HvHDAC2-2, exhibit differential expression across tissues and seed developmental stages and between cultivars with varying seed size, associating them with seed development. Their expression responds to jasmonic acid (JA), abscisic acid (ABA), and salicylic acid (SA), implying an association with stress resistance. This suggests a role for HvHDAC2-1 and HvHDAC2-2 in the epigenetic regulation of barley seed development and stress response.

Hordeum vulgare

Stress induction in immature barley pollen rapidly reorganizes chromatin modifications (H3K4me2, H3K9ac, H3K9me2, H3K27me3), establishing a new stable pattern within 24 hours. This indicates cell fate transition is completed early during induction. Trichostatin A (TSA) stimulated embryogenesis in pollen with gametophytic chromatin patterns. However, TSA administered to embryogenic pollen reversed chromatin markers to a gametophytic profile, halted embryogenesis, and caused pollen death.

Hordeum vulgare

Phosphorylation at histone H3 threonine 11 (H3Thr11ph) occurs in plant mitosis and meiosis, contrasting with mammalian cells. In plants, H3Thr11ph distributes along entire condensed chromosomes, while H3Ser10ph and H3Ser28ph localize to centromeric/pericentromeric chromatin. H3Thr11ph initiates in prophase, ends in telophase, and correlates with chromosome condensation, independent of heterochromatin distribution. Cantharidin treatment induced interphase H3Thr11ph, particularly in pericentromeric regions. These dynamics indicate histone modifications are highly specific and suggest divergent histone codes between plants and animals.